This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A129277 #8 Feb 16 2025 08:33:05
%S A129277 1,2,8,42,241,1444,8867,55320,349009,2220242,14215521,91487834,
%T A129277 591285123,3834960060,24947236547,162704291214,1063516446543,
%U A129277 6965286759424,45696734431169,300262228345720,1975679169075314
%N A129277 Column 1 of triangle A129276; a(n) is the coefficient of q^n in the squared q-factorial of n+1.
%H A129277 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/q-Factorial.html">q-Factorial</a>.
%F A129277 a(n) = [q^n] Product_{i=1..n+1} { (1-q^i)/(1-q) }^2.
%o A129277 (PARI) a(n)=polcoeff(prod(i=1,n+1,(1-x^i)/(1-x))^2,n)
%Y A129277 Cf. A129276, A129278.
%K A129277 nonn
%O A129277 0,2
%A A129277 _Paul D. Hanna_, Apr 07 2007